First version of injection with annotation on parameter

ChangeLog.md

@@ -17,8 +17,9 @@ New features:
 - [KT-11692](https://youtrack.jetbrains.com/issue/KT-11692) Support Spring model diagrams for Kotlin classes
 - [KT-11574](https://youtrack.jetbrains.com/issue/KT-11574) Support predefined Java positions for language injection
 - [KT-2428](https://youtrack.jetbrains.com/issue/KT-11574) Support basic use-cases of language injection for expressions marked with @Language annotation
-- Add comment or @Language annotation after "Inject language or reference" intention automatically
+- [KT-11472](https://youtrack.jetbrains.com/issue/KT-11472) Add comment or @Language annotation after "Inject language or reference" intention automatically
 - Apply injection for the literals in property initializer through property usages
+- Enable injection in Kotlin by annotation function or method parameter with @Language annotation
 - [KT-11807](https://youtrack.jetbrains.com/issue/KT-11807) Use function body template when generating overriding functions with default body
 
 Issues fixed:

idea/src/org/jetbrains/kotlin/idea/injection/KotlinLanguageInjectionSupport.kt

@@ -103,11 +103,13 @@ class KotlinLanguageInjectionSupport : AbstractLanguageInjectionSupport() {
         }
     }
 
-    fun findAnnotationInjectionLanguageId(host: KtElement): String? = doFindAnnotationInjectionLanguageId(host)
+    fun findAnnotationInjectionLanguageId(host: KtElement): String? {
+        val annotationEntry = findAnnotationInjection(host) ?: return null
+        return extractLanguageFromInjectAnnotation(annotationEntry)
+    }
 }
 
-private fun doFindAnnotationInjectionLanguageId(host: KtElement): String? {
-    val annotationEntry = findAnnotationInjection(host) ?: return null
+fun extractLanguageFromInjectAnnotation(annotationEntry: KtAnnotationEntry): String? {
     val firstArgument: ValueArgument = annotationEntry.valueArguments.firstOrNull() ?: return null
 
     val firstStringArgument = firstArgument.getArgumentExpression() as? KtStringTemplateExpression ?: return null

idea/src/org/jetbrains/kotlin/idea/injection/KotlinLanguageInjector.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.idea.injection
 
+import com.intellij.codeInsight.AnnotationUtil
 import com.intellij.openapi.progress.ProgressManager
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.TextRange
@@ -27,6 +28,8 @@ import org.intellij.plugins.intelliLang.Configuration
 import org.intellij.plugins.intelliLang.inject.InjectorUtils
 import org.intellij.plugins.intelliLang.inject.config.BaseInjection
 import org.intellij.plugins.intelliLang.inject.java.JavaLanguageInjectionSupport
+import org.jetbrains.kotlin.idea.util.findAnnotation
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
 import java.util.*
 
@@ -140,7 +143,14 @@ class KotlinLanguageInjector : LanguageInjector {
         val argumentIndex = (argument.parent as KtValueArgumentList).arguments.indexOf(argument)
         val ktParameter = ktFunction.valueParameters.getOrNull(argumentIndex) ?: return null
 
-        return findInjection(ktParameter, Configuration.getInstance().getInjections(KOTLIN_SUPPORT_ID))
+        val patternInjection = findInjection(ktParameter, Configuration.getInstance().getInjections(KOTLIN_SUPPORT_ID))
+        if (patternInjection != null) {
+            return patternInjection
+        }
+
+        val injectAnnotation = ktParameter.findAnnotation(FqName(AnnotationUtil.LANGUAGE)) ?: return null
+        val languageId = extractLanguageFromInjectAnnotation(injectAnnotation) ?: return null
+        return InjectionInfo(languageId, null, null)
     }
 
     private fun findInjection(element: PsiElement?, injections: List<BaseInjection>): InjectionInfo? {

idea/tests/org/jetbrains/kotlin/psi/KotlinInjectionTest.kt

@@ -299,4 +299,46 @@ class KotlinInjectionTest : AbstractInjectionTest() {
             }
             """
     )
+
+    fun testInjectionWithUsageInFunctionWithMarkedParameterWithAnnotation() = assertInjectionPresent(
+            """
+            import org.intellij.lang.annotations.Language
+
+            val v = "<caret>some"
+
+            fun foo(@Language("HTML") s: String) {}
+
+            fun other() { foo(v) }
+            """,
+            languageId = HTMLLanguage.INSTANCE.id, unInjectShouldBePresent = false)
+    
+    fun testInjectionOfCustomParameterWithAnnotation() = assertInjectionPresent(
+            """
+            import org.intellij.lang.annotations.Language
+
+            fun foo(@Language("HTML") s: String) {}
+
+            fun other() { foo("<caret>some") }
+            """,
+            languageId = HTMLLanguage.INSTANCE.id, unInjectShouldBePresent = false)
+
+    fun testInjectionOfCustomParameterInConstructorWithAnnotation() = assertInjectionPresent(
+            """
+            import org.intellij.lang.annotations.Language
+
+            class Test(@Language("HTML") val s: String)
+
+            fun other() { Test("<caret>some") }
+            """,
+            languageId = HTMLLanguage.INSTANCE.id, unInjectShouldBePresent = false)
+
+    fun testInjectionOfCustomParameterDefaultCallWithAnnotation() = assertInjectionPresent(
+            """
+            import org.intellij.lang.annotations.Language
+
+            fun foo(@Language("HTML") s: String) {}
+
+            fun other() { foo(s = "<caret>some") }
+            """,
+            languageId = HTMLLanguage.INSTANCE.id, unInjectShouldBePresent = false)
 }